Process of coal distillation



May 23, 1933. A; .1. A. HERENG PROCESS OF COAL DISTILLATION 11, 1928 4Sheets-Sheet 1 Filed Dec.

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PROCESS OF CGAL DISTILLATION' Filed Dec. 11, 1928 4 Sheets-Sheet 2 L Jr]U Ii May'23, 1933. J HERENG 1,909,956

PROCESS OF COAL DISTILLATION' Filed Dec. 11, 1928 4 Sheets-Sheet 3 y 23,1933- A. J, A. HERENG 1,909,956

PROCESS OF COAL DISTILLATION Filed Dec. 11, 1928 4 Sheets-Sheet 4nvvmmy; flare] dnarr/(2 rd flerery Patented May 23, 1933 PATENT. OFFICEALFRED JEAN ANDRE HEBENG, F PARIS, FRANCE PROCESS OF COAL DISTILLATIONApplication filed December 11, 1828, Serial lji'o. 825,188, and inFrance November 8, 1928.

Persons skilled in the art are aware of the interest that attaches toextracting tars from fuels previous to combustion thereof and of themany processes or methods that have been put into operation with a viewof obtaining the aforesaid result.

Said methods or processes may be classified in two main groups:

According to the processes of the first group, the coal to be treated isnot in contact with the heating fluid and heat is transmitted through apartition.

According to the processes of the second group the coal to be treated isheated internally by the heating fluid.

This invention relates to the second mentioned method, and, accordingthereto, the fuel to be treated, previously dried and heated up toapproximately the softening point,

26 is laid on a travelling grate pervious to fluids, as, for instance,on a power chain grate.

It is a well known fact that the best temperature for obtaining tars bylow temperature distillation is included between 300 and 500 0.; infront of and above the metal apron, there is a distillation chamberwherein the fuel is heated up to the above mentioned optimumtemperature. Such heating may be ensured by combustion in the com- 30partment of any available fuel, whether gaseous, liquid or solid.

One of the characteristic features of my invention consists in thepossibility of heating the fuel to be distilled by means of the gasobtained from the distillation either by burning the same, since it iscombustible, or through heating it up to an adequate temperature, say700 C. Of course radiation from the walls of said distillation chamberoooperates in heating the raw fuel that is laid on the metal grate orconveyor. 1

On the other hand, the links of the chain are at a sufficiently hightemperature, when they come again forwards after a complete 5revolution, suflicient to cooperate, in the heating of the fuel.Furthermore, said heating has the effect of reducing the amount of dustwhich passes through the grate coming from the drying device, therebypreventing coal dust from passing through the grate.

Another essential feature of my invention is that the gaseous productsof the distillation are drawn under the fuel layer by suction chestswherein a lower ressure is maintained than in the distillatlon chamber.

I provide, therefore, a fuel layer heated from above, from below, andwithin its mass, said layer resting on a conveyor pervious to gases, thegaseous products being drawn underneath into suction chests.

The vapor and gaseous products are partly condensable and will givedistillation gases having a high calorific power. These are the gasesthat can be used, as already stated, for heating the fuel in thedistillation chamber.

The heavy tars laden with dust withdrawn from the first condensationdevices, are returned to the fuel in the distillation chamber; theycooperate in reducing the amount of dust which passes through the grate,they get distilled anew in the fuel layer on contact with the nascenthydrocarbons and the distilled gases are sucked into the lower suctionchests as above explained.

Beyond the distillation compartments, there is arranged anothercompartment, which may be the combustion chamber of a boiler, or aquenching and cooling metal box for the semi-coke; but under thiscompartment extends the conveyor (that is to say the chain grate) sothat the fuel passes automatically rom the first to the secondcompartment without any interference from outside.

As will be readily realized, such a device permits: 35

(a) Either simply extracting the primary tars and tar oils andhydrocarbons such as benzol and toluol and burning the semi-coke andgases.

As a matter of fact, owing solely to the movement of the conveyor, thesemi-coke passes from one compartment to the other at a temperature ofapproximately 500 C. and it is necessary only to draw air through chestslocated under the conveyor in order readily to cause combustion.

The gases are sent into the second com partment or combustion chamberwherein the co-operate, jointly with the semi-coke, in eating, forinstance, a steam generator. 1

Part of the gases may, indeed, be utilized, as already stated, to ensurethe heating of the distillation compartment through direct combustion.

(6) Or else, extracting, as in the previous case, the primary tars,burning the semi-coke in the combustion chamber, and, instead of sendingback into the latter the collected gases, housing them in a gasometerfor industrial or domestic use.

In this case, heating of the fuel in the distillation chamber may beensured by a part of the gases previously heated up to an adequatetemperature in a regenerator, so that the gas produced may not be mixedwith other gases which are liable to alter the richness thereof.

The regenerator or gas heater may be heated by any routine means(producer gas, etc.) and, especially, by hot gases from the boiler oreven by a part of the rich gas produced. The location of the regeneratorshould be so selected as to minimize radiation losses, forinstance,'directly above the distillation chamber.

(0) Or again, extracting the primary tars, as above indicated, storingthe rich gas in a gasometer, and quenching the semi-coke so as toprevent combustion thereof, and utilizing this solid fuel for someulterior, industrial or domestic use.

The compactness of said semi-coke may be increased in the course of itstravel through the distillation chamber by means of a loose chain,resting thereon and suitably weighted, and the slack side of which willensure com.- pression of the softened fuel down to hardening at the endof distillation, without ingeriiering with the continuous travel of theThe pressure of said second chain may be adjusted as desired byincreasing or decreasing the slack.

(d) Or, lastly, extracting the primary tars and rich gases, as aboveindicated, also the water gas and the air gas by sending the semi-cokeon to another chain grate or into a producer whereon or whereincombustion of the semi-coke is-efiected by the oxygen of steam or by theoxygen of air in accordance with the routine water-gas or producer gasmanufacturing methods.

In order to make my invention more clearly understood I have illustratedvarious embodiments thereof which will be successively described) in andby drawings appended hereto and wherein the views' are shown inelevation with parts in vertical section:

Figure 1 illustrates a device for performing the first mentioned processin which only the primary tars and oils are extracted while thedistillation gases partly serve for heating the distillation chamber,the remainder of them being burnt in the boiler.

Figure 2 shows a device for performing the right, the drying device S,the distillation compartment D, the combustion chamber C and the boilerV. Underneath, the chain grate G.

As will be apparent, the chain grate is the grate with which the boilerwould be normally equipped, but it extends forward under thedistillation compartment D and the drying device S.

The drying device, indicated as an example, may be constituted byvertical channels wherethrough the raw coal moves down by gravity andheated by combustion gases from the boiler.

Dried and heated, the coal falls down on to the grate Whereon thethickness of the layer is regulated by the grate P. The coal travelsfreely through chamber D, heated up to 600-- 650 C. and gets distilled.The semi-coke passes into the combustion chamber C wherein it is burntby air blown into suction chests A. Screen E permits adjusting theamount of heat that the combustion chamber transmits by radiation to thedistillation chamber. Said amount of heat, may, indeed, be sulficientalone to keep the combustion chamber at optimum temperature.

The hydrocarbons obtained by the distillation are detarred and are ridof their oils by the usual means. B is a separator wherein the gasesbubble in hot tar. The heavy tars, which settle down, are laden withcoal dust; they are sent back, through L, into the distillation chamberD wherein they are freed of dust and redistilled. M is a rotary tarseparator, M an oil removing column.

The gases, detarred and rid of their oils, are sent to the burners 0where complete or partial combustion thereof is caused depending on theextra heat to be provided for the distillation chamber. Excess gasespass under screen E and are burnt in combustion chamber 0.

In the embodiment illustrated by Figure 2, where the same referenceletters denote the same devices as on Figure 1, a fraction of thecollected gases circulates in a closed circuit in order to ensureheating of the distillation chamber D. Said gases go into regenerator Rwherein they are heated up to a sufliciently high temperature. They passinto the distillation chamber D and flow through the fuel layer to whichthey give up some of their actual heat and they are then drawn intosuction chambers H together with the hydrocarbons released by thedistilled fuel. A suitably shaped member Q rests on the fuel bed andprevents gases from passing from one compartment into the othercompartment.

As shown on said Figure 1, regenerator R is heated b burners 0 that useeither producer gas rom an auxiliary generator (not shown), or even coaldistillation gas. The regenerator might also be heated by combustiongases from the boiler.

In the device illustrated by Figure 3 it is contemplated to extractsemi-coke in pulverized form. On issuing from the condensationapparatus, the cooled distillation gas is led to suction chamber 1,passes through the conveyor and the semi-yoke layer which gives upthereto its actual heat and is cooled. The gas thus partly heated goesto regenerator R and goes through the same cycle as in the foregoingcases.

The semi-coke, after having gone through the cooling chamber T, passesinto a crusher J wherein it is powdered before complete cooling.

Figure 4 contemplates extraction of the semi-coke in agglomerated form.An adjustably tensioned endless chain K, of same width as the fuellayer, presses down on the latter while this is soft, that is to say inthe course of distillation. Said chain is free and taken along by themotion of the fuel so that no relative movement is caused between thelayer and the two chains K and G. The hardened semi-coke is next cooledas in chamber T according to the same process as in the previous cases.On leaving grate G, the semicoke accumulates in hoppers after havingpassed over a sieve U whereby pea coke is separated.

Having now particularly ascertained and described the nature of my saidinvention as well as the manner in which the same is to be performed, Ideclare that what I claim 1s:

1. The process of low temperature distillation of coal comprising thefololwing steps: arranging the fuel in a substantially continuous layer,heating said layer, and circulating heavy tar containing coal dustthrough the layer by suction applied to the under side of the layerwhereby the coal dust is removed.

2. The process of low temperature distillation of coal comprising thefollowing steps: arranging the coal in a continuously travelling gaspervious and substantially continuous layer, heating said layer, suctionto the under side of the layer at a plurality of points while a portionof the gases of distillation and the heavy tar containing coal dust arethe layer whereby the coal dust is removed.

and applyingconducted to the top of 3. The process of low temperaturedistila lation of coal comprising the following steps: arranging thecoal in a substantially continuous layer, heating said layer in adistillation chamber, circulating heavy tar containing coal dustthroughthe layer by suction applied to the under side of the layer in the saiddistillation chamber, and agglomerating the semi-coke in the samechamber wh reby the coal dust is removed.

4. The process of low temperature distillation of coal comprising thefollowing steps: arranging the coal in a substantially continuous layer,heating said layer in a distillation chamber, circulating heavy tarcontaining coal dust through the layer by suction applied to the underside of the layer in the said distillation chamber, and agglomeratingthe semi-coke in the said chamber by means of a chain loosely hung overthe said layer of fuel and pressing on the same where by the coal dustis removed.

5. The process of low temperature distillation of coal comprising thefollowing steps: arrangingthe coal in a continuously travelling gaspervious and substantially continuous layer, heating said layer in adistillation chamber, applying suction to the under side of the layer inthe said distillation chamber at a plurality of points while a portionof the gases of distillation and the heavy tar containing coal dust areconducted to the top of the layer, and agglomerating the semicoke in thesame chamber whereby the coal dust is removed.

6. The process of low temperature distillation of coal comprising thefollowing steps arranging the coal in a continuously travelling gaspervious and substantially continuous layer, heating said layer in adistillation chamber, applying suction to the under side of the layer inthe said distillation chamber at a plurality of points while a portionof the gases of distillation and the heavy tar containing coal dust areconducted to the top of the layer whereby the coal dust is removed, andagglomerating the semi-coke in the said chamber by means of a chainloosely hung over the layer of coal and pressing on the same at otherpoints towards the end of the travel of the said fuel through the saiddistillation chamber.

In testimony whereof I aflix my signature.

ALFRED JEAN ANDRE "Euro.

